Tuberous sclerosis complex (TSC) is a tumor syndrome that affects about 1 in 6000 live births. TSC causes physical and mental suffering from the development of hamartomatous tumors in multiple organs including the brain, kidneys, heart, lungs, and skin. Current treatments for TSC skin tumors involve surgery, which leaves permanent and disfiguring scars. Our long-term goal is to exploit recent genetic and molecular discoveries to develop novel and targeted therapies for TSC patients. Our overall objective is to develop models for TSC skin tumors that will allow rapid testing of new drugs and drug combinations, and investigation of drugs applied topically. In our preliminary studies, we have derived cells from TSC skin tumors that are null for tuberin, shown that TSC skin tumor cells are more sensitive to rapamycin and IFN-gamma than TSC fibroblasts, demonstrated our ability to cultivate these cells using an in vitro skin equivalent, and successfully transplanted human skin equivalents onto immunodeficient mice. We hypothesize that cells derived from TSC skin tumors will show greater sensitivity to rapamycin and IFN-gamma compared to cells from TSC normal-appearing skin using in vitro (monolayer and skin equivalent) and xenograft models. Our specific aims are: 1) To use in vitro monolayer and skin equivalent models to determine the effects of rapamycin and IFN-gamma on TSC skin tumor cells, and 2) To use a xenograft mouse model to determine tumor characteristics and the effects of rapamycin and IFN-gamma on human TSC skin tumor cells. The immediate result of these studies, using human TSC tumor cells, will provide important preclinical data for trials with rapamycin and IFN-gamma. The development of these model systems will allow future modifications for high- throughput screening of drug libraries using in vitro models, and pre-clinical testing of so-identified therapeutic agents using the xenograft model. Investigators will be able to test drug combinations more rapidly than in clinical studies, selecting only optimal combinations for study in humans. Different formulations of topically administered agents can be tested using the xenograft model, something that is not possible with current animal models. Finally, these in vitro and xenograft models can be used to investigate TSC tumor microenvironment and drug mechanisms of action, increasing our understanding of how these hamartomatous tumors form and respond to treatment. [unreadable] [unreadable] [unreadable]